韩城矿区晚石炭世以来的升降运动及其控煤效应

Uplift-subsidence movement and its control effect on coal in Hancheng Mining area since Late Carboniferous

升降运动是控制煤层聚积与赋存的首要地质因素,是构造控煤研究的重要内容之一。在韩城矿区4大井田各选取一个具有代表性的钻孔,应用沉降史分析理论和方法,研究该矿区自晚石炭世以来的升降运动特征及其对聚煤作用和煤层赋存状态的控制效应。研究表明,自晚石炭世以来,研究区先后经历了区域性沉降、不均匀抬升和局部沉降,分别发生在晚石炭世~中三叠世、晚三叠世~中新世、上新世~第四纪。升降运动对聚煤作用过程及煤层赋存状态有重要的控制作用。聚煤作用因沉降速率加快而停止,1 000 m的总沉降量促进了煤化作用的进行和煤层气资源的形成,后期抬升使部分煤层遭到剥蚀,同时也使部分煤层埋深变浅,便于开采利用。

Uplift-subsidence movement is the primary geological factor to control the accumulation and occurrence of coal seams;it is also one of the important research contents on structural control of coal. According to the stratum information from four representative drillings in Hancheng mining area, the characteristics of uplift-subsidence movement since Late Carboniferous Epoch and its control effect on coal-accumulation and the occurrence state of coal seams are researched using subsidence history analy- sis theory and method. The research results show that the area experienced successively regional subsid- ence from Late Carboniferous to Middle Triassic ,uneven uplift from Late Triassic to Miocene, and local subsidence from Pliocene to Quaternary since Late Carboniferous Epoch. The uplift-subsidence move- ment played an important control role in the accumulation and occurrence of coal seams. The coal accu- mulation came to a stop due to the subsidence accelerated;the coalification was promoted and coalbed methane resources was formed since the total settlement of more than one thousand meters;the parts of the coal seams wear eroded, and the other part of the coal seams shallowed for easy to miming during later tectonic uplift movement.